(i) Field of the Invention
The present invention relates generally to a void filling device, and more particularly to a void filling device comprising a void filling material to fill a void space by expanding with heat and a holder for retaining the void filling material.
(ii) Description of the Related Art
Techniques to improve the noise insulation properties, the damping properties, and the strength by filling the void space inside a car pillar or the like have commonly been used. As described in the Publication of Japanese Unexamined Patent Application No. 1-164641, a void filling material formed by inserting a compressed urethane foam material between two pieces of sheet-like thermosetting foaming material is well known.
The void filling material is adhered to the inner wall of a tubular component, such as a center pillar, before the assembly of the component. Adhesion is achieved by taking advantage of the inherent adhesion of the thermosetting foaming material, or by using an adhesive, a double-faced adhesive tape and the like. According to the description, when the component is heated for drying after being painted, the sheet-like thermosetting foaming material begins to foam and expand.
Since the thermosetting foaming material is gradually softened by the heat and its restraining force to keep the urethane foam in the compressed state is reduced, the original shape of the urethane foam is gradually restored. Then, the urethane foam with the restored shape functions as a core member of the void filling material, which leads the void filling material to expand into a preferred configuration. Thus, the void space inside the center pillar or the like is filled with the expanded thermosetting foaming material and the urethane foam with the restored shape, so that preferred noise insulation properties, damping properties, and the strength can be obtained.
In the prior art described above, the tubular component, such as a center pillar, is formed by butting two members each having a U-shaped cross section and integrating the members by means of welding or the like. The void filling material has been adhered to the flat inner wall of one of the two members prior to the integration of the members
However, when the tubular component, such as a center pillar, is formed not by integrating two members but directly from a pipe or the like, there is a problem that it is difficult for the void filling material to be adhered to the inner wall. The same is true with the case where a through hole is formed in a cylindrical blank and the void filling material is fixed within the through hole using a clip or the like.
The object of the present invention is to provide a void filling device, which facilitates insertion of a void filling material into a component having tubular structure and hold of the void filling material therewithin.